(The northeastern United States is much larger than Peru but has only about 5,000 species of plants; yet here we have many up-to-date botanical compendia called floras by which plant species may be identified.)
Presently we noticed a tangled, yellow-flowered, sticky-leaved, ratty-looking wild tomato, not much different from the weedy tomatillo (Lycopersicon peruvianum) so widespread in Peru. Nevertheless, we took immediate notice of it, for tomatoes belong to the potato family and this was a relative of a cultivated species. And wild or weedy tomatoes must always be taken seriously!
Not only did we collect herbarium specimens of this weedy tomato, describing it in our notebook under the serial number 832 (i.e., the 832nd collection of this expedition), but we also gathered two dozen of its green-and-white striped berries, which are smaller than cherries. We smashed the berries between newspapers to dry their seeds, and weeks later, we mailed them together with other tomato seed samples to Charles Rick, tomato geneticist at the University of California, Davis, who, we had heard, would want to grow them in his experimental plots.
This is an old story, of course, and illustrates the network nature of the study of natural history. Taxonomists do this sort of thing for each other all the time, unasked and as a matter of course, whether they know each other personally or not. “I will collect seeds for you of your special plant group, if you will collect seeds for me of mine.”
Back at the University of Wisconsin, a thank-you note from Prof. Rick informed us that our No. 832 was most unusual and perhaps useful in plant breeding. Not until 1976, however, after 14 years of research, did Rick (1976) publish this as a new species, naming it Lycopersicon chmielewskii in honor of the late Tadeusz Chmielewski, a Polish tomato geneticist and Rick’s associate. Another of our tomato collections, obtained below Curahuasi, he described as yet another new and local species, Lycopersicon parviflorum. That certainly made us feel good: to have been involved in the discovery of two new species in this small though important genus. Previously, taxonomists recognized only seven species of wild tomato, and now there were nine! Our story could have ended here, of course, and still be a good one, what with us showing off the type of specimens housed in the University of Wisconsin Herbarium to interested students and telling tall expedition tales of haciendas and vicuñas, potatoes and tomatoes. But there was more to come.
In July 1980, a letter from Dr. Rick told the following story. When 17 years before, he had received our seeds numbered 832, he crossed their progeny with a commercial tomato variety to improve the latter’s characteristics. After nearly 10 (!) generations of back-crossing the first-generation (F1) hybrids, and with subsequent selection, Rick was able to produce several new tomato strains with larger fruit and a marked increase in fruit pigmentation. But most importantly, they had greatly increased the content of soluble solids, mainly fructose, glucose, and other sugars, all attributes of prime importance to the tomato industry. While the usual type of tomato contains between 4.5 and 6.2% soluble solids, the genes from our